Perth Airport is a vital public transport facility that operates 24 hours a day, seven days a week. It provides an essential link for business and leisure travel and meets the needs of regional communities, the resource sector, and the freight and export industry.

More than 90 per cent of aircraft movements are related to passenger services. Other aircraft movements incorporate a range of freight and general aviation uses, including emergency services operations. 

Perth Airport currently has two intersecting runways. The main runway 03/21 is positioned in a north-south alignment and is 3,444 metres long. The cross runway 06/24 is positioned in a northeast-southwest alignment and is 2,163 metres long.

Both ends of a runway can be used for aircraft landings (arrivals) and take-off (departures). The direction being used is referred to as the operating or duty runway.

Runway selection decisions are made by Airservices Air Traffic Controllers. The selection of the operating runway is based on many considerations, including weather, local airspace, traffic demand, and runway maintenance requirements.

The weather, and in particular wind speed and direction, is generally the main factor in determining which runways are used because aircraft typically take-off and land into the wind for safety and performance reasons. This means that Perth’s seasonal wind patterns affect usage of the different runway directions. Runway 21 tends to be used more frequently in the warmer months due to southerly winds, while runway 03 tends to be used more frequently in the cooler months when the predominant wind direction tends to be northerly. Runway 06 and Runway 24 are used in strong crosswind conditions or when the main runway is closed for maintenance activities.

An operating mode is the use of a certain runway, or a combination of runways. For operations at Perth Airport, aircraft arrivals from the north and departures to the south are referred to as the South Flow, while arrivals from the south and departures to the north are referred to as the North Flow. The current runway modes are shown below.